Rotary kiln.



NTTED STATES PATENT OEEIOE.

ALEXANDER rnOMsoN MAOFAELANE, on ROCHESTER, ENGLAND;

ROTARY KILN.

SPECIFICATION forming part of Letters Patent No. 684,996, dated October22, 191.01. Application filed January 2, 1901. Serial No. 41,820. `(Nomodel.)

To all whom it may concern:

'Be it known that I, ALEXANDER THOMSON MACFARLANE, asubject of the Queenof Great Britain, residing at Rochester, in the county of Kent, England,have in-vented a certain new and useful Improvement in Rotary Kilns, ofwhich the following is a full, clear, and exact description, such aswill enable others skilled in the art to which it appertains to make anduse the same, reference being had to the accompanying drawings, formingpart of this speciiication.

This invention relates to a new and useful improvement in rotary kilnsused for the manufacture of cement and the like, and has for its objectto dry the powdered coal, slurry, or slip, dac., so that the heatemployed in burning the cement or other material in a kiln 'may also beused as a drying medium, thus utilizing the heat radiated from the kilnand preventing the same from being wasted.

Y Generally speaking, my invention consists in enveloping a rotary kilnwith a casing throughout any desired portion or, for that matter, thewhole of its length, into which casing the material to be dried isintroduced, means being provided in the casing and attached thereto orto the periphery of the kiln, whereby the material to be dried is notonly agitated, so that the little particles thereof are subjected to thedrying heat, but said particles of material are propelled from the feedto the discharge end of the drying-chamber.

In the drawings I have shown several forms of my invention applied to awell-known type of rotary kiln.

Figure l represent-s a rot-ary kiln in elevation with my improved dryingattachment arranged in position thereon, said attachment being shownpartly in section. Fig. 2 is a vertical cross-sectional view on line 22, Fig. l. Fig. 3 is a side elevational view of a kiln with my improveddrying apparatus in a slightlymodified form in position thereon. Fig. 4:is a sectional view on line i 4, Fig. 3.

In the drawings, A indicates a rotary kiln proper, which is preferablyarranged slightly inclined, as usual, the forward end of said kiln beingreceived in a hood B, mounted 5o upon a wheeled truck, as is usual,through which hood finely-pulverized coal is designed to be introduced,as is well understood. Y

O indicates the stack,into which the rear and elevated end of the rotarykiln is received, said stack carrying off the products of combustionfrom the kiln. The cement or other material to be burned is introducedinto the rear or elevated end of the kiln, and upon ignition ot' thecombustible material introduced at the front end the kiln by beingrotated will gradually feed the material therein in a forward direction,the rotation of the kiln presenting dilferent particles of the materialto be burned to the action of the heat contained therein.

The kiln proper usually consists of a metallic casing lined inside withfire-brick, annular tracks o. being arranged at suitable points on theperiphery of the kiln, which tracks cooperate with supporting rollers,whereby the kiln is supported between its ends. I have not deemed itnecessary to show this supporting or driving mechanism in the drawings,as it forms no part of my invention; but I will state that the usualpractice, depending upon the length of the kiln, is to arrangesupporting-rollers at intervals of about fifteen or twenty feet apartwhere the kiln is of any considerable length (the kilns being usuallyfrom forty to sixty feet long) and that the driving mechanism may beeither located at the front end of the kiln or at any other pointdesired.

Referring now particularly to my improvement, D indicates a casing,preferably of sheet metal, said casing surrounding the body of the kilnproper and extending over any desired portion of its length. As shown inFig. l, this casing is located some distance from the body of the kiln,so asto provide the chamber or space into which the material to be driedis introduced. The ends of this casing are preferably closed by suitablewalls or flanges, which extend inwardly and embrace the body of thekiln, while openings d are arranged in the top of the casing D for theescape of moisture evaporated from the material being dried.

Suitable supports d are provided for the casing D to hold it in astationary position, and an inlet-spout or feed-opening d2 is arroo bodyof the kiln within the casing D, said,

blade extending suiiiciently near said casing D to agitate and move thematerial intro-.

duced therein to be dried from the inlet-opening to thedischarge-opening. It is obvious that the heat radiated from the kilnwill thus be utilized in drying the material in the dryingchamber,abovedescribed,the kiln proper carrying the agitating and propelling blades,whereby all particles of material in the drying-chamber are subjected tothe drying influence of the radiated heat from the kiln.

In Fig. 3 I have shown a conveyer G for conducting the material to bedried to the inlet-opening cl2, and instead of having thedischarge-opening from the drying-chamber in the bottom portion of thelower end thereof I arrange a series of buckets or elevators at thelower end of the chamber, said buckets being secured to and rotatingwith the kiln proper, whereby the dried material is elevated or liftedby the buckets and discharged into the spout I-I.

In Fig. 5 I have shown a construction in which the kiln is provided withilights I to agit-ate and propel the material to be dried and also aseries of buckets I', which lift the material in its passage through thedryingchamber and carry it over the body of the kiln, the material uponreaching the highest point in the drying-chamber being discharged fromthe buckets and falling over the body of the kiln to the bottom of thedrying-chamber, where it is either propelled onward by the iiights oragain lifted and carried over the kiln, as before described. tion I mayhave either the outlet or discharge opening at the bottom, or thebuckets may lift and discharge the dried material at the side, as beforedescribed.

I am aware that minor changes in the arrangement, construction, andcombination of the several parts of my device can be made andsubstituted for those herein shown and described without in the leastdeparting from the nature and principle of my invention.

In this construc' ceases In the event that the drier becomes choked atany time the relief-doors D in the lower portion of the casing D may bedropped to discharge the load. A screw conveyer D" may also be used inthe bottom of the casing D below the paths of the spirals or angledflights, the purpose of said screw conveyer being to force the materialtoward the discharge end of the machine, as shown in Fig. 7, or thisscrew conveyer can be used in the bottom of the casing and the spiral orother agitating medium entirely omitted.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. In an apparatus of the character described,the combination with arotary cementkiln, of a casing enveloping a portion of said kiln, and adevice secured to and movable with the rotary kiln, for receiving,agitating, and propelling material to be dried, and which is introducedbetween the kiln and the enveloping casing, substantially as described.

2. In an apparatus of the character described, the combination with arotary cementL kiln, of a casing surrounding a portion of the length ofsaid kiln, said casing being provided with heads or inturned iianges atits ends which embrace the kiln and forma dryingchamber, inlet andoutlet openings leading to and from said drying-chamber, a devicemounted upon the rotary kiln between said heads and Within thedrying-chamber for agitating and propelling the material to be dried,which material is introduced between the kiln and the casing forming thedrying-chamber, substantially as described.

3. In an apparatus of the character described,the combination with arotary cementkiln, of a casing surrounding a portion of the length ofsaid kiln and forming a dryingchamber, a spiral blade mounted upon thekiln and rotating therewith in said dryingchamber for agitating andpropelling the material to be dried which is introduced in the chamberbetween the kiln and casing, and buckets secured to the kiln within thecasing for elevating the material in the dryingchamber, substantially asdescribed.

In testimony whereof I hereunto affix my signature, in the presence oftwo witnesses, this 6th day of December, 1900.

ALEXANDER THOMSON MACFARLANE.

Witnesses:

SIDNEY Mos'rYN VAUe-HAN, STANLEY WILLIAM lIopGEs.

